Engineers developing digital systems find themselves increasingly more interested in digital word flow than in the waveforms of particular signals. For example, instruction and address sequences in a microprocessor are usually of more interest to the designer and diagnostician than the waveform on a signle address or instruction line.
Some past efforts have been directed towards providing digital instruments which are capable of producing trigger pulses in response to the detection of selected digital words. This trigger pulse can be used to trigger an oscilloscope or other display device. See, for example, U.S. Pat. No. 3,805,255 by C. Mark Baker entitled "Scanning Light Emitting Diode Display of Digital Information." Other recent efforts have provided a listing of sequential binary words. See, for example, the Hewlett-Packard Journal of January 1974.